Field
Exemplary embodiments of the present invention relate to a backlight unit and a liquid crystal display (LCD) including the same.
Discussion of the Background
Conventional displays are being replaced by thin flat panel displays such as liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs).
An LCD may include a liquid crystal panel having liquid crystals injected between a thin-film transistor (TFT) substrate and a color filter substrate. Since the LCD may not emit light by itself, a backlight unit for supplying light may be located behind the TFT substrate. Transmittance of light emitted from the backlight unit may be adjusted by the arrangement of the liquid crystals.
Backlight units may be classified into direct-illumination type and edge-illumination type according to the position of a light source. In an edge-illumination type backlight unit, a light source may be disposed on a side of a light guide plate (LGP). The edge-illumination type backlight unit may be used for relatively small-sized LCDs, such as laptop computers and notebook computers. The edge-illumination type backlight unit may provide uniform light, have a long useful life, and be advantageous for making LCDs thinner.
When a light-emitting diode (LED) (i.e., a point light source) is used as the light source of the edge-illumination type backlight unit, a hot spot (i.e., a bright portion) may be created on a portion of a liquid crystal panel due to characteristics of the point light source. In particular, the hot spot may occur when light emitted from the light source forms a bright portion on the liquid crystal panel, and an area around the bright portion may appear dark (a dark portion). The bright or dark portions of the hot spot may degrade the quality of a display device.
In addition, while the LED is placed on a side of the LGP to emit light toward the LGP, part of the emitted light may leak, that is, may fail to enter the LGP.
In particular, when an LED emitting white light is used as the light source, a hot spot may be created on the liquid crystal panel, and the hot spot may make the luminance of the LCD non-uniform.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the inventive concept, and, therefore, it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.